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When seven of the Chicago Police Department's most elite cops were charged with crimes including armed robbery, aggravated kidnapping and home invasion- and one of them was even accused of planning a murder-the nation's second largest police force was thrown into turmoil.

They were members of a unit known as "SOS," the Special Operations Section, the department's answer to violence that once made Chicago the murder capital of the country. But what 60 Minutes has learned paints a disturbing picture of a chain of command that put such a premium on getting guns and drugs off the streets that officers felt justified breaking the law to do so.

One of those indicted officers is 30-year-old Keith Herrera. He's been telling his story in private to federal investigators. Now, out on bail, he tells it publicly to Katie Couric and takes 60 Minutes inside a world where cops who did so much good ended up accused of doing so much wrong.

Prosecutors have said Herrera and his partners were bold, brazen and malicious. His response?

"I say I was doin' my job. I went to work every day, put my star on, put my gun on and got the bad guys off the street," he tells Couric. "I was doing my job and I was told I was doing a good job."

Until a year and a half ago, Herrera was a rising star in the Special Operations Section. But his promising career collapsed when he and six of his partners were accused of terrorizing the very streets they were policing-busting into homes without warrants, making illegal arrests, and holding people hostage until they handed over guns and drugs-all at a time the SOS unit had virtual autonomy in Chicago's worst neighborhoods.

Asked what his marching orders were, Herrera says, "Get the guns, and get the drugs off the street. No matter what. At any cost. Just get 'em off."

Herrera says the mandate from his bosses was clear: the ends justify the means. SOS hauled in big caches of weapons and drugs, and across the city, the crime rate plummeted.

"Policing the way we did it, there were just certain steps that you had to take," Herrera says. "We're dealing with convicted felons, we're dealing with bad people, we're dealing with drug dealers. If you want these people to go to jail, you have to cross the line sometimes."

Asked what his supervisors thought of his techniques, Herrera tells Couric, "Keep it up. Long as you got the guns, long as you got the drugs, long as you're getting the bad guys, keep it up.' And if they tell you 'Keep it up,' you keep it up."

He says it was like making a deal with the devil. For example, if a suspect tossed a gun to avoid arrest, Herrera says it was obvious how to make the case stick: lie, and say the gun never left the suspect's hand.

"Do you want that guy that's running down the street, that just shot somebody to not go to jail 'cause he threw the gun? Or do you want him to go to jail because he never let the gun out of his hand? He knows what he's gotta do, and I know what I gotta do," Herrera says.

"I get it. But it's also making stuff up," Couric points out.

"It's not making stuff up, it's doing what you gotta do to put bad guys in jail," Herrera argues.

"Changing the story," Couric remarks.

"It happens. That's all I can tell you," Herrera says.

"So there are no Boy Scout police officers doing it by the book out there?" Couric asks.

"Maybe," Herrera says. "This isn't, you know, Podunk, Iowa. This is the city of Chicago. You gotta do a job."